Hematological and histological changes induced by adrenocorticotropic hormone and formaldehyde stressor in the domestic fowl.

Abstract

In the present experiment, changes of percentage of leucocytes in the adult chicken blood induced by ACTIH injection and histological changes of lymphoid tissues and adrenals in the young chick induced by formaldehyde stressor, were examined.Hematological changes: Relative heterophilia and lymphopenia were observed in the treated chicks which were injected with 10mg of ACTH intravenously or intraperitoneally, and were not observed in the chickens injected with the same dose of ACTH intramuscularly or subcutaneously. It was found that pricking of comb has some stressor agentical effect upon blood in the fowl, and also it was suggested that Selye's stress concept should be applicable to the chicken.Histological changes: Single comb white leghorn cockerels 3-4 weeks old were used. They were injected with 1 cc of 4% formaldehyde intramuscularly 3times during 36hours. They were sacri ficed at the end of the period of 12hours after the last injection. The decrease in weights of thymus, spleen and bursa Fabricii and hypertrophy of adrenal gland were observed. Histologically, in the thymus of the treated chicks, the thymocytes of the thymus cortex drained into medulla, so that the demarcation between cortex and medulla became unvisible, and naked reticular cells appeared in the thymus cortex. The number of Hassal-body increased relatively, and the PAS positive degenerating intercellular granules also seemed to increase in their number. In the speen, severe involution of the lymph follicle in the white pulp, and heteropoiede in the red pulp were observed.Hyperplasia, hypertrophy, mitotic figures of the interrenal cells and loss of chromaffin substances in the chromaffiiin cells were observed in the adrenal gland. In the bursa Fabricii, though involutic change of the follicles was observed, other striking changes could not be confirmed histologically or cytologically. From these facts, it could not be decided whether the bursa Fabricii is a true lymphoid organ or not.These changes were comparable to those in mammals, and function of bursa Fabricii were discussed in the present parper.